Spinal arachnoiditis. What is the clinical spectrum? II. Arachnoiditis induced by Pantopaque/autologous blood in dogs, a possible model for human disease.

Experimentally induced chronic arachnoiditis was studied over a one-year period in beagle dogs. All animals demonstrated severe extensive changes at postmortem which were strikingly similar to those reported in man. Arachnoid inflammation, fibrosis, and adhesions were often associated with nerve roots embedded in collagen. These changes were present in all four experimental dogs, and were absent in four controls. In spite of having pathologically severe changes of arachnoiditis, two of four dogs appeared clinically normal. We suggest that the clinical appearance of chronic arachnoiditis in this animal model may reflect the human experience, wherein presentations may vary from merely complaints of back pain to severe sensory-motor impairment.